Release valve



Jan. 10, 1933. c BANKS 1,893,757

RELEASE VALVE Filed Sept. 10. 1931 INVENTOR. g

A TTORNE Y.

Patented Jan. 10, 1933 CHARLES M. BANKS, F PHILADELPHIA, PENNSYLVANIA RELEASE VALVE Application fil ed September 10, 1931. Serial No. 562,028.

My invention relates generally to release valves for use in the operating pistons of hydraulic jacks and more particularly to a valve for use in connection with a hydraulic jack as covered in my United States Patent Number 1,758,64l0 issued May 13, 1930.

The main object of the present invention is to provide a valve adapted for mounting in the operating piston of a hydraulic jack and so arranged that it will remain closed during the normal pumping operation of that piston in creating the hydraulic pressure for operating the jack but will be automatically opened to permit the escape of that pressure and the lowering of the jack by simply forcing the piston downward to its greatest extent and holding the same until said pressure escapes.

Another object is to provide a valve seat adapted for mounting in the piston and a valve mounted in the said seat and normally pressed in engagement therewith by a spring of sufficient strength to overcome the lifting effect on the valve caused by the reciprocation of the piston, there being a projecting stem on valve adapted to contact and open the usual inlet valve at the inner or lower end of the cylinder when the piston is forced inward to its greatest extent and at the same time overcome the tension of the said spring and raise the release valve from its seat.

Another object is to provide a screen arranged on the release valve in such manner as to collect and prevent the escape of particles of the oil used in the jack which may become vaporized by the intense rush or flow of air passing through the valve when the same is opened.

A further object is to provide a release valve of this kind in a simple, positive and durable form.

With these and other objects in view as will appear hereinafter, the invention resides in the novel construction and arrangement of parts as hereinafter set forth and claimed reference being had to the accompanying drawing wherein:

Figure 1 is a vertical cross section through a hydraulic ack showing the operating piston thereof equipped with my release valve.

Figure 2 is detached side elevation of the release valve, stem and oil retainer screen.

Figure 3 is a detached plan view of the oil retainer screen alone.

Referring now more particularly to the drawing, the type of hydraulic jack shown is that covered by my prior patent hereinbefore referred to and the present invention is shown as applied to the operating piston A thereof. This piston A is reciprocated in the pump cylinder B by a handle C and forces air through the inlet valve D into the cylinder E whereby the load carrying plunger F therein is raised as will be understood. As in usual practice the cylinders B and E beneath the valve D and plunger F are filled with a suitable oil.

In accordance with the present invention the piston A has a central threaded opening 1 in which the end of the piston rod '2 is 7 threaded, the said end of the rod 2 projecting below the face of the piston to receive a lock nut 3 to hold the piston firmly in place. The lower end of the piston rod 2 is provided with an axially aligned recess 4 extending inward for some distance and being internally threaded as shown at 5 from its mouth inward through the greater part of its length. An axially extended relatively smaller escape passage 6 is provided in the piston rod 2 and is extended upward from the closed inner end of the recess at to a point near the upper end of the rod 2 where it extends radially outward as at 7 and opens at the outer periphery of the rod. A valve seat 5 or cage 8 is provided and the same is in the form of a tubular shell threaded on its outer periphery for mounting in the threaded recess 4: and having a central bore 9 and angular outwardly flared ends 10 and 11 the end 10 serving as a valve seat. The release valve 12 comprises a head 13 with an angular seating face 14 complementary to the valve seat 10 and a stem 15 extended from the said head as shown. The valve 12 has its stem15 passed loosely through the bore 9 of the valve seat 8 from which it depends a considerable distance when the seating face 14 of the valve head 13 rests in the valve seat 10. When mounted as shown an expansion coil spring 16 placed in a recess 17 in the valve head 12 and braced between this head and the inner closed end of the recess 4; acts to press the valve to the seat 10. A pin 18 secured near the lower end of the valve stem 15 acts to limit the upward movement of the valve as will be understood. The oil retainer screen 19 is in the form of a truncated cone of line screen or similar reticulated material having a collar or band 20 around its upper end which collar is adapted for mounting on the valve stem 15 beneath the valve seat 8 as shown.

The valve stem 15 at its lower end is adapted to engage the apex or upper end of the conical inlet valve head 21 which is normally pressed to its seat in the inlet valve D by an expansion coil spring 22 arranged as shown to bear upward on the said head 21. In the normal operation of the piston A the compressed air created by each downward stroke will force the inlet valve head 21 downward and open whereby the air will force the plunger F upward, the valve head 21 being then immediately closed by the pressure of the air and by the spring 22. The strength of the spring 16 of the release valve is just sufficient to overcome this upward pressure on the inlet valve head 21 and also to withstand the upward pressure on the release valve during each downward stroke of the piston A. Air ports 23 are formed through the head of the pump cylinder B to admit air for the operation of the pump.

After the load carrying plunger F has been raised as far as necessary by the action of the piston A and it is desired to lower the plunger the piston A is forced downward in the cylinder B as far as possible and beyond the limit of its normal movement causing the end of the valve stem 15 to engage the upper end of the inlet valve head 21 and force the same open. At the same time the increased resistance of the spring 22 together with the pressure of the air in the ack cylinder E thus released by the valve head 21 will overcome the force of the spring 16 and cause the release valve 12 to raise whereupon the air will flow through the bore 9 of the valve seat and will pass through the air escape passage 6 in the piston rod 2 and emerge from the upper end of this passage. This action will continue while the piston A is held down and until the plunger F has been fully lowered. The oil retainer cone 19 will act as a stop and will gather vaporized particles of the oil to prevent the loss of the same as will be understood.

lVhile I have herein set forth a certain preferred embodiment of my invention it is un'- derstood that I may vary from the same in minor structural details so as best to construct a practical device for the purposes intended, not departing from the spirit of the invention and within the scope of the appended claim.

I claim:

In a device of the kind described, embodying a hydraulic jack and connected pump cylinder and piston operatively mounted therein, there being an inlet valve mounted at the bottom of the cylinder in alignment with the piston, and the said piston having a central, threaded opening into which is threaded the end of the piston rod, the lower end of the piston rod having an axially aligned internally threaded cylindrical recess, and the piston rod having an axially extended air escape passage leading from the said recess and emerging from the rod outwardly of the pump cylinder, an exteriorly threaded tubular valve shell mounted in the said cylindrical recess of the piston rod, the said shell having a central bore therethrough and having a valve seat formed at its upper end, a release valve seated on the said valve seat, the said valve having a stem loosely passed down through the central bore of the said shell and adapted to impinge upon the said inlet valve when the said piston is pressed down to its limit, and resilient means for holding the said valve to its seat for opening the said inlet valve upon the full downward movement of the piston.

In testimony whereof, I affix my signature.

CHARLES M. BANKS. 

